1. (Field of the Invention)
This invention relates to an optical brake controller or master controller located at the operator's control position in a railway car, which is used to output brake commands or force commands as an electric signal, depending on the step position of the operator's control handle. In particular, the invention relates to a system which uses a transmission type optical switch consisting of a light emitting element and a light receiving element.
2. (Prior Art)
Utility Model Kodai No. 57-58906, illustrated in FIGS. 4 to 7, is one example of the prior art for a brake or master controller using an optical type transmission switch. FIG. 4 is a schematic side view of the main portion of the brake controller or the master controller. FIG. 5 is a schematic diagram of the cross section along line c--c of FIG. 4. FIG. 6 is a schematic diagram of the cross section along line d--d in FIG. 4. FIG. 7 is a schematic diagram of the cross section along line e--e in FIG. 4.
In FIG. 4-FIG. 7, 1 is the rotating shaft, 41, 42, 43 are light blocking plates, 51a, 52a, 53a re light emitting elements and 51b, 52b, 53b are light receiving elements. There is a rotating shaft 1 inside the main body (not indicated in the FIG.) which can rotate freely, and is connected to a handle (not indicated in the FIG.) operated by the driver. The light blocking plates 41, 42, 43 are fixed on the circumference of the above-mentioned rotating shaft 1 essentially perpendicular to the center in the axial direction of the rotating sahft 1 and they have transmitting areas 41a,41b, 42a, 43a which are formed by notching the outer rims in the circumferential direction. The light emitting element 51a and the light receiving element 51b are placed on opposite sides of the light blocking plate 41 in the axial direction (vertical direction in FIG. 4) of the rotating shaft 1 to sandwich the light blocking plate 41. In the same manner, there are elements 52a and 52b for the light blocking plate 42 and elements 53a and 53b for the light blocking plate 43.
As shown by the arrows in FIG. 5-FIG. 7, when the light blocking plates 41, 42, 43 rotate clockwise in the figure, initially, in the first step position, the transmitting area 41a shifts to the area between the light emitting element 51a and the light receiving element 51b, so that the light receiving element 51b receives the beam from the light emitting element through the transmitting area 41a and converts it into an electrical signal and this signal becomes the brake command or the force command.
When it rotates clockwise further and reaches the second step position, the transmitting area 42a, shifts to the area between the light emitting element 52a and the light receiving element 52b and in the same manner as described above, the light receiving element 52b receives the light and converts it to an electrical signal. After this, as above, the brake command or the force command is output as an electric signal. (The problem that the invention tries to solve)
However, since it is the outer rim of the light blocking plate 41, 42, 43 which forms the transmitting area 41a41b, 42a43a, in the controller of the prior art, which uses the optical type transmission switch, the position of the optical switch for these transmission areas is also on both sides of the outer rim of the light blocking plate 41-43, and also the rotation angle of the light blocking plate is limited to approximately 100.degree.-150.degree.. Because the many step positions must be determined inside the angle, so that there are 3 or 2 optical switches located on the outer rim of one light blocking plate, it is impossible to obtain more than this number of outputs. In addition, to obtain a larger number of outputs, the number of combinations of the light blocking plate and the optical switches must be increased, as shown in FIG. 4, which increases the overall size of the unit. In other words, the example of the prior art described above cannot supply many outputs on a small scale, which represents a problem.